To maintain hardcore environment, The forging should be ultra-difficult, let alone Obtaining ingredients is already incredibly hard: We have also implemented gem combining level limitations. Please observe the following table to understand how the limitations work out as time progress.
- First 30 days == Lv3
- Next 60 days == Lv4
- Next 120 days == Lv5
- Next 240 days == Lv6
- Next 480 days == Lv7

I am just point out when your reached a +4 gem and trying to forge to make a +5-6 using a Lv3 gem